Change the Bone Rotation (Quaternions) of an Armature in text script
Might be hard finding someone that remembers how to use python in 2.49. The 2.49 api docs are still available here.

The second example on the armature page might be what you are looking for - while the docs list Get() as a function the example uses arm_ob.getData()

scn= Scene.GetCurrent()
arm_ob= scn.objects.active
arm_data= arm_ob.getData()
bones= arm_data.bones.values()

for bone in bones:
    # use bone here